Performance of JavaScript (Node.js) Applications

Modern Node.js web applications must be fast, responsive, and stable. But how do you achieve maximum performance when every request counts? The book "JavaScript (Node.js) Application Performance" is a practical guide that will help you turn slow code into an efficient and scalable product.

What this book is about

You will learn how the V8 engine works under the hood, learn to identify bottlenecks using profiling and benchmarks, and master optimization techniques that actually work in production. The book covers all key aspects of Node.js performance:

• Profiling and monitoring — Chrome DevTools, Node.js Inspector, clinic.js, flame graphs.
• Memory management — memory leaks, garbage collection, data structure optimization.
• Asynchrony and the event loop — proper work with promises, async/await, timers, and microtasks.
• I/O optimization — streams, buffering, connection pools, working with databases.
• Caching — in-memory cache, Redis, CDN, HTTP caching.
• Load testing — Artillery, autocannon, k6, result analysis.
• Scaling — clustering, worker threads, load balancing.

Who this book is for

The book is intended for developers who already write in JavaScript/Node.js and want to reach the next level. You will get practical recipes and ready-made solution templates that can be immediately applied in a project. It will be especially useful for:

• Middle and Senior developers working with high-load systems.
• DevOps engineers who want to understand the behavior of Node.js applications under load more deeply.
• Team leads and architects responsible for service performance.

What you will learn

• How to find and eliminate bottlenecks in code.
• Why your service is "slow" and how to fix it without a global refactoring.
• How to avoid memory leaks and reduce resource consumption.
• How to properly design asynchronous operations for maximum throughput.
• How to conduct load testing and interpret its results.

The book contains real-world examples, analysis of typical mistakes, and step-by-step instructions. After reading it, you will be able to confidently optimize any Node.js applications — from microservices to monoliths.